Semiconductor optical gain

About: Semiconductor optical gain is a research topic. Over the lifetime, 5997 publications have been published within this topic receiving 96505 citations.

Photonics : optical electronics in modern communications

Abstract: 1. Electromagnetic Fields and Waves 2. Rays and Optical Beams 3. Dielectric Waveguides and Optical Fibers 4. Optical Resonators 5. Interaction of Radiation and Atomic Systems 6. Theory of Laser Oscillation and Some Specific Laser Systems 7. Chromatic Dispersion and Polarization Mode Dispersion in Fibers 8. Nonlinear Optics 9. Electro-Optics and AO modulators 10. Noise in Optical Detection and Generation 11. Detection of Optical Radiation 12. Periodic Structures 13. Waveguide Coupling 14. Nonlinear Optical Effects in Fibers 15. Semiconductor Lasers 16. Advanced Semiconductor Lasers 17. Optical Amplifiers 18. Classical Treatment of Quantum Optics, Quantum Noise, and Squeezing A. WAVE EQUATION IN CYLINDRICAL COORDINATES AND BESSEL FUNCTIONS B. EXACT SOLUTIONS OF THE STEP-INDEX CIRCULAR WAVEGUIDE C. KRAMERS-KRONIG RELATIONS D. TRANSFORMATION OF A COHERENT ELECTROMAGNETIC FIELD BY A THIN LENS E. FERMI LEVEL AND ITS TEMPERATURE DEPENDENCE F. ELECTRO-OPTIC EFFECT IN CUBIC 43M CRYSTALS G. CONVERSION FOR POWER UNITS AND ATTENUATION UNITS

Novel method for high resolution measurement of laser output spectrum

Abstract: The spectral spread of the best stabilised semiconductor lasers has been reduced to several megahertz. Conventional spectroscopy techniques cannot offer a spectral resolution fine enough for measuring such a sharp spectrum. The letter proposes a novel method by which 50 kHz resolution can be obtained. The principle, experimental set-up and results are described.

Ge-on-Si laser operating at room temperature.

Abstract: Monolithic lasers on Si are ideal for high-volume and large-scale electronic-photonic integration. Ge is an interesting candidate owing to its pseudodirect gap properties and compatibility with Si complementary metal oxide semiconductor technology. Recently we have demonstrated room-temperature photoluminescence, electroluminescence, and optical gain from the direct gap transition of band-engineered Ge-on-Si using tensile strain and n-type doping. Here we report what we believe to be the first experimental observation of lasing from the direct gap transition of Ge-on-Si at room temperature using an edge-emitting waveguide device. The emission exhibited a gain spectrum of 1590-1610 nm, line narrowing and polarization evolution from a mixed TE/TM to predominantly TE with increasing gain, and a clear threshold behavior.

Single-exciton optical gain in semiconductor nanocrystals

Abstract: Nanocrystal quantum dots have favourable light-emitting properties. They show photoluminescence with high quantum yields, and their emission colours depend on the nanocrystal size—owing to the quantum-confinement effect—and are therefore tunable. However, nanocrystals are difficult to use in optical amplification and lasing. Because of an almost exact balance between absorption and stimulated emission in nanoparticles excited with single electron–hole pairs (excitons), optical gain can only occur in nanocrystals that contain at least two excitons. A complication associated with this multiexcitonic nature of light amplification is fast optical-gain decay induced by non-radiative Auger recombination, a process in which one exciton recombines by transferring its energy to another. Here we demonstrate a practical approach for obtaining optical gain in the single-exciton regime that eliminates the problem of Auger decay. Specifically, we develop core/shell hetero-nanocrystals engineered in such a way as to spatially separate electrons and holes between the core and the shell (type-II heterostructures). The resulting imbalance between negative and positive charges produces a strong local electric field, which induces a giant (∼100 meV or greater) transient Stark shift of the absorption spectrum with respect to the luminescence line of singly excited nanocrystals. This effect breaks the exact balance between absorption and stimulated emission, and allows us to demonstrate optical amplification due to single excitons. Semiconductor nanocrystals have very good light-emitting properties, so have potential as optical amplification media that can be easily processed with solution-based techniques: possible applications include optical interconnects in microelectronics, lab-on-a-chip technologies and quantum information processing. The problem with these structures is that at least two excitons (bound electron–hole pairs) need to be present in a nanocrystal before optical gain can be achieved, and this limits performance. In effect, the excitons annihilate each other before optical amplification can occur. This obstacle has now been overcome using nanocrystals with cores and shells made from different semiconductor materials, constructed in such a way that electrons and holes are separated from each other. This makes optical gain based on single excitons possible, significantly enhancing their promise as a practical optical material for laser applications. Semiconductor nanocrystals seem good candidates for 'soft' optical gain media, but optical gain and lasing is hard to achieve owing to a fundamental optical effect, which involves the problem that at least two excitons need to be present in a nanocrystal to achieve gain, and this limits performance. Here the problem is circumvented by designing nanocrystals with cores and shells made from different semiconductor materials, and in such a way that electrons and holes are separated from each other: this makes possible optical gain based on single excitons, thereby significantly enhancing the promise of semiconductor nanocrystals as practical optical materials for a wide range of lasing applications.

Injection locking properties of a semiconductor laser

Abstract: Injection locking properties of a semiconductor laser have been analyzed, taking into account the injected carrier density dependent refractive index in the active region. It has been found that this dependence significantly affects the injection locking properties, giving rise to a peculiar asymmetric tuning curve and dynamic instability. The instability originates from the intermode interaction via the modulation in the injected carrier density caused by intensity beat. The detuning dependence of the direct modulation response characteristics inside and outside of the locking range have also been examined.